While the U.S. GAO estimates that half of the short term general hospitals with 200 beds or more will install hospital medical information systems by 1990, physician utilization of these systems remains low. A recent estimate indicates that only 20 percent of the physicians associated with hospitals that have installed HMISs use the system to enter medical orders. Results of a preliminary study of one multispecialty group suggests that characteristics of the networks through which information, patients, and influence flow among physicians affect the extent to which they utilize training of house staff. Consequently, this study is designed to determine how characteristics of physician networks affect their utilization of a HMIS. In particular, characteristics of these networks that affect physician exposure to information concerning the advantages of utilizing the HMIS and the speed with which such information moves through the network of physicians will be identified. Also, the relative importance of other factors such as the physician's specialty, medical education, and involvement in the training of house staff in accounting for differential use of the HMIS will be examined. Data will be collected from the attending and house staff of Methodist Hospital, an 1160 bed private general hospital in Indianapolis. These data will be subjected to network analysis and path analysis. Based on the findings of this study recommendations will be prepared concerning the development of programs designed to increase physician utilization of hospital medical information systems. The findings of this study will also provide insight into ways to more effectively involve physicians in the implementation of recent developments in computer-assisted consultation, clinical data banks, and computer-assisted medical education.